3. Earnings and economics: There are plenty of earnings to digest including quarterly results from some big box retailers. Walmart(WMT), Home Depot(HD), TJ Maxx(TJX) and Dick's Sporting Goods(DKS) are due to report before the open. DeVry Education(DV) will report after the close.

SanDisk (SNDK)shares are ones to watch Tuesday. The tech firm was trading down nearly 2% premarket.